Open Access

ARTICLE

S. Abdullah¹
Structural Durability & Health Monitoring, Vol.4, No.4, pp. 181-198, 2008, DOI:10.3970/sdhm.2008.004.181
Abstract This paper describes a technique to identify the important features in fatigue road spectrum loading, for which these features cause the majority of the total damage. Fatigue damaging events, called bump segments, are extracted from the spectrum loading using a wavelet-based algorithm, called Wavelet Bump Extraction (WBE). This algorithm is also used to produce a shortened mission signal that retains most of the fatigue damage whilst preserving the cycle sequences. The bump identification process has been evaluated by analysing two road spectrum loadings having a variable amplitude pattern. These data sets were obtained from the strain measurement on the lower… More >

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ARTICLE

Shu Minakuchi¹, Tadahito Mizutani¹, Haruka Tsukamoto², Mayuko Nishio², Yoji Okabe³, Nobuo Takeda¹
Structural Durability & Health Monitoring, Vol.4, No.4, pp. 199-220, 2008, DOI:10.3970/sdhm.2008.004.199
Abstract The authors propose a technique to detect centimeter internal damages in large-scale composite structures, using an optical fiber network running throughout the structure. A Brillouin-based distributed strain sensing system with centimeter-order spatial resolution (pre-pump pulse Brillouin optical time domain analysis (PPP-BOTDA)) was utilized to detect residual non-uniform strain in the damaged area. First, Brillouin spectral response depending on the strain profile within the spatial resolution was revealed. The spectral response depending on strain non-uniformity was experimentally quantified with consideration of the general characteristics of the Brillouin gain spectrum. Then, the damage detection procedure was proposed, based on the spectral response.… More >

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950

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ARTICLE

A. Rama Ch,ra Murthy¹, G.S. Palani¹, Nagesh R. Iyer¹
Structural Durability & Health Monitoring, Vol.4, No.4, pp. 221-230, 2008, DOI:10.3970/sdhm.2008.004.221
Abstract Empirical formulae based on experimental data to evaluate concrete penetration depth under impact loading are often used due to the complexity of the phenomena. Several design codes employ empirical formulae for the design of protective barriers. This paper presents the details of relative assessment of the use of well known empirical formulae for evaluation of concrete penetration depth under impact loading. The empirical formulae employed in the present studies include Conwep, Army corps, Haldar, Ammann and Whitney, UKAEA, BRL, Modified Petry and modified NDRC. Appropriate expressions and limitations for these empirical formulae have been provided. Performance of these empirical formulae… More >

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1178

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ARTICLE

A.B. Mahmud Hasan^1,2, M A Wahab¹, S.M. Guo¹
Structural Durability & Health Monitoring, Vol.4, No.4, pp. 231-240, 2008, DOI:10.3970/sdhm.2008.004.231
Abstract This paper presents details analysis of Heat Affected Zone (HAZ) in High Temperature Vacuum Tube Furnace (HTVTF) to predict fracture region in tube wall due to thermal stress from temperature variation across its thickness. A simple mathematical model is used to illustrate stress concentration arising due to thermal stresses in tube wall and HAZs. Finite element model and analysis were carried out utilizing finite element analysis commercial codes. Combination of thermal stress due to temperature difference determine fracture region. Experimental and simulation results of inside temperature of tube are observed and similar relation have been found. Observation of heat affected… More >

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